CN213649039U

CN213649039U - Composite film for lithium battery packaging

Info

Publication number: CN213649039U
Application number: CN202021508372.2U
Authority: CN
Inventors: 林新土; 李智尧; 贾露; 陈曦; 郑伟
Original assignee: Xiamen Changsu Industrial Co Ltd
Current assignee: Xiamen Changsu Industrial Co Ltd
Priority date: 2020-07-27
Filing date: 2020-07-27
Publication date: 2021-07-09
Anticipated expiration: 2030-07-27

Abstract

The utility model discloses a lithium cell is composite film for packing comprises nylon composite film layer, first bond line, aluminium foil layer, second bond line and polypropylene film layer in proper order from outer to interior, nylon composite film layer is biaxial stretching nylon composite film, comprises extinction polyester film layer, third bond line, first nylon layer, second nylon layer and nylon top layer in proper order from outer to interior. The utility model discloses a complex film is used in lithium cell packing has electrolyte-resistant advantage, helps discerning appearance defects such as towards shell damage and crazing that produce in the plastic-aluminum membrane manufacturing process moreover, has saved one complex process simultaneously to the effect of extinction has been realized.

Description

Composite film for lithium battery packaging

Technical Field

The utility model belongs to the technical field of the film material, concretely relates to composite film is used to lithium cell packing.

Background

At present, lithium ion batteries are widely applied to the fields of digital products, electric automobiles and the like, and packaging materials of the lithium ion batteries mainly comprise a steel shell, an aluminum shell and a soft aluminum-plastic film, wherein the soft aluminum-plastic film is more and more widely applied by virtue of the advantages of light weight, safety and the like.

At present, a nylon film is generally adopted as a surface layer of the aluminum plastic film, but the nylon film is easy to corrode when contacting with an electrolyte to generate a whitening phenomenon. Therefore, in the actual use process, in order to prevent the electrolyte from corroding the nylon film on the surface layer in the aluminum plastic film preparation process, a common method is to compound a polyester film on the surface layer of the nylon film, which not only consumes time and increases cost, but also has the problems of high VOC emission in the production process. And the protective layer of the aluminum plastic film of the existing lithium battery is generally a transparent film layer, so that appearance defects generated in the manufacturing process of the aluminum plastic film are difficult to find.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome prior art's weak point, provide a lithium cell is composite film for packing, solved the problem among the above-mentioned background art.

The utility model provides a technical scheme that its technical problem adopted is: the utility model provides a lithium cell is composite film for packing comprises nylon composite film layer, first bond line, aluminium foil layer, second bond line and polypropylene film layer in proper order from outer to interior, nylon composite film layer is biaxial stretching nylon composite film, comprises extinction polyester film layer, third bond line, first nylon layer, second nylon layer and nylon top layer in proper order from outer to interior.

The polyester used in the extinction polyester film layer is one or more of polyethylene terephthalate and a copolymer thereof, polybutylene terephthalate and a copolymer thereof, and polyethylene naphthalate and a copolymer thereof. The third adhesive layer is one or the combination of maleic anhydride modified polyolefin resin, ethylene-acrylic acid copolymer, ethylene-acrylate copolymer, ethylene-methacrylic acid copolymer.

In a preferred embodiment of the present invention, the thickness of the nylon composite film is 15 to 30 μm.

In a preferred embodiment of the present invention, the outer surface of the nylon composite film and the inner surface contacting with the first adhesive layer are configured as a corona surface.

In a preferred embodiment of the present invention, the inside of the matting polyester film layer is filled with a matte auxiliary agent.

In a preferred embodiment of the present invention, the first nylon layer is filled with carbon black powder.

In a preferred embodiment of the present invention, the second nylon layer and the nylon surface layer are made of nylon 6 resin of film grade.

In a preferred embodiment of the present invention, the thickness of the aluminum foil layer is 35 to 40 μm.

In a preferred embodiment of the present invention, the thickness of the polypropylene film layer is 30 to 80 μm.

In a preferred embodiment of the present invention, the thickness of the first adhesive layer is 3 to 5 μm, and the thickness of the second adhesive layer is 3 to 6 μm. The first bonding layer and the second bonding layer are two-component polyurethane adhesives.

Compared with the background technology, the technical scheme has the following advantages:

1. according to the scheme, the five-layer co-extrusion biaxially-oriented nylon composite film layer is used as the outermost layer, the aluminum foil layer and the polypropylene film layer are combined, the corrosion of electrolyte to the nylon film on the surface layer is effectively prevented, and meanwhile, a polyester film does not need to be additionally compounded on the surface layer of the nylon film, so that the time and labor are saved;

2. the first nylon layer that has adopted the packing to have carbon black powder in the outer nylon composite film layer of this scheme, still set up the extinction polyester rete outside the first nylon layer, make the rete present for the matte black, in case the discovery dashes appearance defects such as shell damage and crazing, is discerned easily.

Drawings

Fig. 1 is a schematic structural view of a composite thin film layer for lithium battery packaging in example 1.

The composite film comprises a 1-nylon composite film layer, a 11-delustering polyester film layer, a 12-third adhesive layer, a 13-black nylon layer, a 14-second nylon layer, a 15-nylon surface layer, a 2-first adhesive layer, a 3-aluminum foil layer, a 4-second adhesive layer and a 5-polypropylene film layer.

Detailed Description

It should be noted that the term "inner" refers to a direction close to the lithium battery, the term "outer" refers to a direction away from the lithium battery, and the terms "first", "second", and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Example 1

Referring to fig. 1, the composite film for packaging the lithium battery sequentially comprises a nylon composite film layer 1, a first adhesive layer 2, an aluminum foil layer 3, a second adhesive layer 4 and a polypropylene film layer 5 from outside to inside, wherein the nylon composite film layer 1 is a biaxially oriented nylon composite film and sequentially comprises a delustering polyester film layer 11, a third adhesive layer 12, a black nylon layer 13 (namely, the first nylon layer), a second nylon layer 14 and a nylon surface layer 15 from outside to inside.

In this embodiment, the matte polyester film layer 11 is made of polyethylene terephthalate filled with a matte auxiliary agent, the third adhesive layer 12 is made of maleic anhydride modified polyolefin resin, the black nylon layer 13 is made of nylon 6 resin filled with carbon black, and the second nylon layer 14 and the nylon surface layer 15 can be made of film-grade nylon 6 resin. The extinction polyester film layer 11, the third bonding layer 12, the black nylon layer 13, the second nylon layer 14 and the nylon surface layer 15 are prepared by five-layer co-extrusion biaxial stretching, and the total thickness is 15-30 micrometers. And, the surface of nylon composite film layer 1, the internal surface of nylon composite film layer 1 and the contact of first bond line 2 all through corona treatment, set up to the corona face.

In this embodiment, the first adhesive layer 2 and the second adhesive layer 4 are two-component polyurethane adhesives, the thickness of the first adhesive layer 2 is 3 to 5 μm, and the thickness of the second adhesive layer 4 is 3 to 6 μm.

The thickness of the aluminum foil layer 3 is 35-40 μm, and the thickness of the polypropylene film layer 5 is 30-80 μm.

The composite film for packaging the lithium battery adopts the five-layer co-extrusion biaxially-oriented nylon composite film layer 1 as the outer layer, and a polyester film is not required to be additionally compounded on the surface layer of the nylon film, so that a compounding process is omitted; the reasonable layer layout and thickness distribution enable the film of the embodiment not only to have the advantage of electrolyte resistance, but also help to identify appearance defects such as shell punching damage and small cracks generated in the manufacturing process of the aluminum plastic film, and simultaneously realize the extinction effect.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims

1. The utility model provides a lithium cell is composite film for packing which characterized in that: the composite nylon film is a biaxially oriented nylon composite film and sequentially comprises an extinction polyester film layer, a third adhesive layer, a first nylon layer, a second nylon layer and a nylon surface layer from outside to inside.

2. The composite film for lithium battery packaging as claimed in claim 1, wherein: the first nylon layer is filled with carbon black powder.

3. The composite film for lithium battery packaging as claimed in claim 1, wherein: and a matte auxiliary agent is filled in the extinction polyester film layer.

4. The composite film for lithium battery packaging as claimed in claim 1, wherein: the outer surface of the nylon composite film layer and the inner surface in contact with the first adhesive layer are arranged to be corona surfaces.

5. The composite film for lithium battery packaging as claimed in claim 1, wherein: and the second nylon layer and the nylon surface layer are made of film-grade nylon 6 resin.

6. The composite film for lithium battery packaging as claimed in claim 1, wherein: the thickness of the nylon composite film layer is 15-30 mu m.

7. The composite film for lithium battery packaging as claimed in claim 1, wherein: the thickness of the aluminum foil layer is 35-40 mu m.

8. The composite film for lithium battery packaging as claimed in claim 1, wherein: the thickness of the polypropylene film layer is 30-80 mu m.

9. The composite film for lithium battery packaging as claimed in claim 1, wherein: the thickness of the first bonding layer is 3-5 mu m.

10. The composite film for lithium battery packaging as claimed in claim 1, wherein: the thickness of the second bonding layer is 3-6 mu m.